1. Field
A vane pump is disclosed herein.
2. Background
Various devices have been utilized to provide double steering force in a steering device of vehicles. In the case of a hydraulic steering device, a power steering pump to supply oil pressure may be used. Various types of pumps may be utilized as a power steering pump, and in general, a vane pump having high efficiency, small volume, and weight, and generating less vibrations is utilized.
FIG. 1 is a schematic cross-sectional view of a related art vane pump. The vane pump may include a body 1 and a pump cartridge 3 installed in the body 1. The pump cartridge 3 may include a rotor 31 rotatably installed within the body 1, and a cam ring 30, in which the rotor 31 may be installed. In addition, a plurality of slots may be formed in the rotor 31, and a vane 32 may be slidably installed within each of the plurality of slots. The vane 32 may be pressurized toward an inner wall of the cam ring 30, thus preventing leakage between an end portion of the vane 32 and an inner wall surface of the cam ring 30.
The rotor 31 may be coupled to a rotational shaft 50 rotated by a driving force from an engine, so that the rotor 31 may be rotated together with a driving of the engine. When the rotor 31 is rotated, the vane 32 may also be rotated together to force-feed a fluid within a space defined by outer surfaces of the vane 32, cam ring 30, and rotor 31.
In the vane pump having the foregoing structure, continuous friction may be caused between an end of the vane 32 and the cam ring 30, and thus, the vane 32 and the cam ring 30 may be abraded. Friction may also be caused between inner walls of the slots of the rotor 31 and the vane 32. Thus, in order to reliably operate the vane pump for a long period of time, damage due to abrasion needs to be minimized.
In the related art vane pump used as a steering device of a vehicle, the cam ring 30 is formed of low-alloy steel, and the vane 32 is formed of high-alloy steel. Also, the rotor 31 is formed of carbonized and quenched gear steel. However, the cam ring and the rotor have low processibility and require a heat treatment for a long period of time, increasing manufacturing costs, and high coefficients of friction thereof result in significant damage due to abrasion.